Carbon black has historically been the reinforcing agent of choice for rubber-based products such as tires and extruded and molded goods. Carbon black, which is produced by the thermal decomposition of oil and natural gases, greatly enhances mechanical strength and resistance to abrasion and has, in the past, been an economically attractive approach to improving the physical properties of rubber products. However, the increasing demand for other oil or gas derived petrochemicals, combined with the decreasing supply of oil and natural gas, has prompted searches for a carbon black replacement.
Reinforcing silica's higher costs and poorer performance has previously prevented it from competing with carbon black as a reinforcing filler for rubber. However, with recent and projected oil and gas price increases and with the development of new silica manufacturing processes, amorphous and fine particle size silicas have become available which are considered to be economically competitive with carbon black. A major effort to make reinforcing silica competitive with carbon black on a performance basis has evolved as a result of these changing economical factors. One approach is the incorporation into the rubber recipe of reinforcing promoters or coupling agents to effectively bond the silica to the rubber and, at the same time, obtain and/or improve the physical properties of the resulting rubber product.
Accordingly, an object of this invention is to provide novel reinforcing promoters.
Another object of this invention is to provide reinforced rubber compositions exhibiting improved properties.
A further object of this invention is to provide improved vulcanizable silica-containing rubber compositions.
A further object of this invention is to provide reinforcing promoters that will effectively bond the reinforcing materials to rubber.
Further objects, aspects, as well as the several advantages of the invention will be apparent to those skilled in the art upon reading the specification and the appended claims.